Ship and boat hulls and other underwater structures are commonly coated to keep barnacles, tubeworms, and other marine organisms from adhering to the hull or other structure. Such organisms can damage the structure to which they adhere and, in the case of ship and boat hulls, significantly increase the drag on the hull as it moves through the water. This disadvantageously reduces the speed which the hull can achieve and increases the fuel required to drive the ship or boat through the water.
Fouling has heretofore been dealt with by coating or impregnating a vessel or structure with a composition containing a microbiocide. Among the microbiocidal compounds heretofore employed to retard fouling by marine organisms are tributyl tin, copper dioxide, and copper hydroxide. All of these compounds are water-soluble, self-leaching, and highly toxic. Current federal regulations prohibit the use of coatings which contain tributyl tin and regulations limiting the use of copper dioxide and copper hydroxide are being promulgated in ever increasing numbers in the interest of protecting the marine ecosystems.
There is accordingly a current and continuing need for new coatings which can be employed to retard the fouling of vessels and underwater structures with the effectiveness of those heretofore available but which will, at the same time, not require the highly toxic compounds currently employed in anti-fouling coatings.
Icing is another pervasive problem. For example, ice may accumulate in a thickness of many inches on the rigging of a boat fishing in Arctic or sub-Arctic waters. This can make the vessel top heavy and significantly affect the stability of the vessel. Also, drag is increased with a concomitant increase in fuel consumption.
Equally well known problems arise when ice and mud accumulate on other structures. As a single example, the freezing of water to the inner walls of a coal hopper can make it difficult and expensive to unload the coal from the hopper.
Consequently, there is also a need for coatings which can be employed to inhibit the build-up of ice and mud on a variety of structures in circumstances where such build-up would be disadvantageous.